I started out by adding pictures into my bible with tracing paper and scrapbook glue, and then started painting over some pages in my old prayer and bible study notebooks--covering up the parts that aren't really ever for anyone else's eyes but God's, but keeping the parts that were especially meaningful and helpful to me. It is something I do a little bit of here and there and it gives me so much joy, because it isn't pressured and anxiety inducing like so many of my commissioned projects and art jobs often are. Also, I feel like I'm making a treasure to give my kids some day--a piece of my heart. I like to listen to my audio bible and sermons and podcasts, or sometimes just music, while I do it.
It's also something I have fun doing with my kids, and my son has added several art pages to his bible, too.